backend.md

2023 Fall FE Backend Interview

Architecture Task

You are tasked with developing a server-side application that accepts image uploads every 1.5 seconds. Your application is responsible for compressing and saving the images on disk, and storing each image's name in a database. Without writing any code, briefly describe a possible software schema you could use to solve this task. You should be sure to mention and describe the advantages and disadvantages of:

• The web framework you will use to process and save the image
• What application protocol you will use to receive the image
• The database engine you will use to store files

Programming Task

Given a set of program nodes that depend on each other, write a Python3 method getSafeRunOrder that returns a valid order to run the programs in such that no program will run before all of its dependencies are running.

Example

nodes = {'a','b','c','d'} 
dependencies = {'a->b','a->d','b->c','d->c'}

Explanation: There are 4 programs labelled a through d. The notation a->b means that the program a is dependent on the program b. You can assume every program's name consists of lower-case a-z and has a length of at least 1 (i.e it matches the regular expression [a-z]+).

Valid output: Valid safe run orders for this input include:

• [c, b, d, a]
• [c, d, b, a]

Your function can return any of them.

Starter Code

from typing import Set, List

def getSafeRunOrder(nodes: Set[str], dependencies: Set[str]) -> List[str]:
    return "TODO: Implement the method"

def test():
    nodes = {'a', 'b', 'c', 'd'} 
    dependencies = {'a->b','a->d','b->c','d->c'}
    order = getSafeRunOrder(nodes, dependencies)
    print(order)
    assert order in [['c','b','d','a'],['c','d','b','a']]

if __name__ == "__main__":
    test()